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May 21, 2011
05/11

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Surface modifications to composite materials induced by long term exposure in low earth orbit (LEO) were dominated by atomic oxygen erosion and micrometeoroid and space debris impacts. As expected, calculated erosion rates were peculiar to material type and within the predicted order of magnitude. Generally, about one ply of the carbon fiber composites was eroded during the 70 month LDEF experiment. Matrix erosion was greater than fiber erosion and was more evident for a polysulfone matrix than...

Topics: ALUMINUM, TEFLON (TRADEMARK), MATHEMATICAL MODELS, PERFORATION, CRATERING, CRATERS, DAMAGE...

Defects in fiber composite components produce changes with respect to the vibrational characteristics of the material. These changes can be recognized in the form of a frequency shift or an alteration of the damping process. The present investigation is concerned with questions regarding the possibility of a utilization of the changes in suitable defect-detecting inspection procedures. A description is given of a method for measuring the damping characteristics of a specimen. This method...

Topics: NASA Technical Reports Server (NTRS), DAMAGE ASSESSMENT, FIBER COMPOSITES, FREQUENCY SHIFT,...

NASAâ€™s Orbital Debris Engineering Model was designed to calculate orbital debris fluxes on spacecraft in order to assess collision risk. The newest of these models, ORDEM 3.0, has a number of features not present in previous models. One of the most important is that the populations and fluxes are now broken out into material density groups. Previous models concentrated on debris size alone, but a particleâ€™s mass and density also determine the amount of damage it can cause. ORDEM 3.0...

Topics: NASA Technical Reports Server (NTRS), SPACE DEBRIS, MATHEMATICAL MODELS, RISK, MATERIALS, DAMAGE...

This report discusses a methodology that can be used to assess the effect of foreign body impacts on composite structural integrity. The described effort focuses on modeling the effect of a central impact on a 5 3/4 inch filament wound test article. The discussion will commence with details of the material modeling that was used to establish the input properties for the analytical model. This discussion is followed by an overview of the impact assessment methodology. The progress on this effort...

Topics: NASA Technical Reports Server (NTRS), COMPOSITE STRUCTURES, DAMAGE ASSESSMENT, IMPACT DAMAGE,...

As a consequence of preparations concerning the International Space Welding Experiment (ISWE), studies were performed to better understand the effect of molten metal contact and electron beam impingement with various fabrics for space suit applications. The question arose as to what would occur if the electron beam from the Ukrainian Universal Hand Tool (UHT) designed for welding in space were to impinge upon a piece of Nextel AF-62 ceramic cloth designed to withstand temperatures up to 1427 C....

Topics: NASA Technical Reports Server (NTRS), OUTGASSING, ELECTRON BEAM WELDING, SPACE SUITS, COMBUSTION...

A nonlinear time series approach is presented to detect damage in systems by using a state-space reconstruction to infer the geometrical structure of a deterministic dynamical system from observed time series response at multiple locations. The unique contribution of this approach is using a Multivariate Autoregressive (MAR) model of a baseline condition to predict the state space, where the model encodes the embedding vectors rather than scalar time series. A hypothesis test is established...

Topics: DTIC Archive, PORTO UNIV (PORTUGAL) FACULTY OF ENGINEERING, *MATHEMATICAL MODELS, *MULTIVARIATE...

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This report summarizes work performed in support of the development and demonstration of a structural ceramic technology for automotive gas turbine engines. The AGT101 regenerated gas turbine engine developed under the previous DOE/NASA Advanced Gas Turbine (AGT) program is being utilized for verification testing of the durability of next-generation ceramic components and their suitability for service at reference powertrain design conditions. Topics covered in this report include ceramic...

Topics: BOOSTER ROCKET ENGINES, LIFE CYCLE COSTS, SCHEDULES, COSTS, MATHEMATICAL MODELS, RESEARCH...

A review of some approximate analytical models for damaged, fiber reinforced composite materials is presented. Using the classical shear lag stress displacement assumption, solutions are presented for a unidirectional laminate containing a notch, a rectangular cut-out, and a circular hole. The models account for longitudinal matrix yielding and splitting as well as transverse matrix yielding and fiber breakage. The constraining influence of a cover sheet on the unidirectional laminate is also...

Topics: NASA Technical Reports Server (NTRS), DAMAGE ASSESSMENT, FIBER COMPOSITES, FRACTURE MECHANICS,...

A family of advanced weapon systems that deserves special attention comprises aerial autonomous weapons called Unmanned Combat Aerial Vehicles (UCAVs), which are characterized by the ability to loiter in the target area, sense the targets, acquire the targets, and then engage them. Modeling this combination of capabilities in a specific operational setting is necessary for addressing design and operational issues of this weapon. This work focuses on the development of an analytic probability...

Topics: DTIC Archive, Baggesen, Arne, NAVAL POSTGRADUATE SCHOOL MONTEREY CA, *DATA PROCESSING, *UNMANNED,...

A description of a weapons evaluation model and computer program developed to simplify and shorten computation time in solving problems of nonnuclear weapons evaluation. The model assumes a gaussian aiming error distribution and a rectangular target area. Two types of damage functions are considered, corresponding to two different types of weapon-target effects: a fragment-sensitive target (one in which the major damage mechanism is due to fragments) and an impact-sensitive target (one in which...

Topics: DTIC Archive, Snow, Roger, RAND CORP SANTA MONICA CA, *CLOSE SUPPORT, *KILL PROBABILITIES, IMPACT,...

Structural health monitoring (SHM) is a competitive approach for damage detection in aircraft structures, wherein online information is collected and compared with an existing database for the undamaged structure, to obtain real-time information about the presence of damage. The goal of this research is to develop numerical models of inverse problems for damage detection in aircraft structures, which could later be part of an on-board system for SHM. In this work, the numerical modeling has two...

Topics: DTIC Archive, UNIVERSIDADE FEDERAL DE ITAJUBA (BRAZIL) FUNDACAO DE APOIO AO ENSINO-PESQUISA E...

The methodology developed in this study is intended to provide a research engineer with a systematic approach for evaluating the merits and orientation of a target vulnerability research program. The methodology emphasizes consideration of fundamental parameters included in the weapon effects-target interaction descriptive process and the individual relative significance of these parameters in a targeting scheme. The methodology employs a decision tree format for evaluating proposed work. The...

Topics: DTIC Archive, Binninger, G C, SCIENCE APPLICATIONS INC MCLEAN VA, *DECISION MAKING, *KILL...

The paper presents a computer model for developing and evaluating a targeting strategy against an opposing force's lines of communication (LOC). The aim is to obtain the greatest reduction in enemy throughput and the greatest time and cost of repair. The network arcs (road, rail, or waterway segments or transshipment points) are characterized by beginning and ending nodes, upper and lower bounds, interdicted and uninterdicted unit flow costs, repair times and costs, and the probabilities that...

Topics: DTIC Archive, Wollmer, R D, RAND CORP SANTA MONICA CA, *MILITARY OPERATIONS, *MILITARY TACTICS,...

In the computation of damage aggregation to an area target from a salvo of N weapons, the assumption of a cellular target (i.e., a target composed entirely of cells) is often made. This assumption together with the implicit associated assumption of weapon strikes only at the center of those cells constitutes a significant simplification to the real world model with potentially significant errors in the computation. It is the purpose of this paper to eliminate the assumption of cellular targets.

Topics: DTIC Archive, Russak, I. B., NAVAL POSTGRADUATE SCHOOL MONTEREY CA DEPT OF MATHEMATICS, *DAMAGE...

The increased reliance on advanced networking technologies to integrate cutting-edge capabilities has posed tremendous challenges in assuring user legitimacy and preserving the integrity of our network landscape. Without proper network accountability and holistic vulnerability assessment, insider threats can exploit the security vulnerabilities that result from creating an integrated system-of-systems. To detect security illegitimacies, such as unauthorized connections, network security...

Topics: DTIC Archive, NAVAL POSTGRADUATE SCHOOL MONTEREY CA, *DATA TRANSMISSION SECURITY, *VULNERABILITY,...

An improved computer program was formulated to calculate the average blast impulse loads acting on a wall of a cubicle when an explosive charge is detonated within the cubicle. It was devised by the Ammunition Engineering Directorate's Process Engineering Laboratory in connection with the Safety Design Criteria Program and it simplifies an earlier computer program used to calculate data points for the construction of impulse charts in Technical Manual 5-1300, 'Structures to Prevent the Effects...

Topics: DTIC Archive, Levy, Stuart, PICATINNY ARSENAL DOVER NJ, *EXPLOSIVE CHARGES, *WALLS, LOADS(FORCES),...

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Jul 12, 2010
07/10

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Gezari, D. Y.; Schmitz, M.; Mead, J. M

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The Catalog of Infrared Observations and its Far Infrared Supplement summarize all infrared astronomical observations at infrared wavelengths published in the scientific literature between 1965 and 1982. The Catalog includes as appendices the Bibliography of infrared astronomy which keys observations in the Catalog with the original journal references, and the index of infrared source positions which gives source positions for alphabetically listed sources in the Catalog. The Catalog data base...

Topics: CRACK GEOMETRY, MATHEMATICAL MODELS, MEASURE AND INTEGRATION, MICROCRACKS, STRESS INTENSITY...

The Flood Damage Analysis (FDA) Package enables a variety of flood damage computations to be performed using linked hydrologic engineering and flood damage computer programs. A data storage system links the programs and allows the almost automatic transfer of data from one program to another. This package has existed for several years on mainframe computers. Recently, it has been adapted to MS-DOS microcomputers.

Topics: DTIC Archive, Carl, Robert D, HYDROLOGIC ENGINEERING CENTER DAVIS CA, *FLOODS, MATHEMATICAL MODELS,...

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May 22, 2011
05/11

by
Sturms, Francis M., Jr.; Dias, William C.; Nakata, Albert Y.; Tai, Wallace S

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The Mars Pathfinder Project plans a December 1996 launch of a single spacecraft. After jettisoning a cruise stage, an entry body containing a lander and microrover will directly enter the Mars atmosphere and parachute to a hard landing near the sub-solar latitude of 15 degrees North in July 1997. Primary surface operations last for 30 days. Cost estimates for Pathfinder ground systems development and operations are not only lower in absolute dollars, but also are a lower percentage of total...

Topics: AIRCRAFT STRUCTURES, DAMAGE ASSESSMENT, DEBRIS, FAILURE ANALYSIS, LOADS (FORCES), COEFFICIENT OF...

The problem of calculating expected component life under fatigue loading conditions is complicated by the fact that component loading histories contain, in many cases, cyclic loads of widely varying amplitudes. In such a case a cumulative damage model is required, in addition to a fatigue damage criterion, or life relationship, in order to compute the expected fatigue life. The traditional cumulative damage model used in design is the linear damage rule. This model, while being simple to use,...

Topics: NASA Technical Reports Server (NTRS), COMPONENT RELIABILITY, FATIGUE (MATERIALS), LIFE...

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Jul 12, 2010
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No Abstract Available

Topics: DAMAGE ASSESSMENT, COMPUTERIZED SIMULATION, GRAPHITE-EPOXY COMPOSITES, MATHEMATICAL MODELS,...

Let H(t) be the life distribution of a device subject to shocks governed by an integer-valued stochastic process with stationary, independent, nonnegative increments. H(t) is a function of the probabilities PR of surviving the first k shocks, k = 1, 2, ... . We show that H(t) inherits various aging properties (IFR, IFRA, NBU) of the discrete survival function Pk. Analogous results hold in the continuous case where H(t) is the life distribution of a device subject ot wear according to a wear...

Topics: DTIC Archive, Joe,Harry, FLORIDA STATE UNIV TALLAHASSEE DEPT OF STATISTICS, *MATHEMATICAL MODELS,...

Requirements of JTCG/AS test and evaluation resulted in AV (vulnerable area) data being developed for only six cardinal views. These views are defined using the positive and negative directions along the axes through the aircraft centroid. Six views are insufficient for attrition modeling purposes. For example, P001 required 26 views which must be obtained by projection of the six cardinal views. This can be accomplished using either an R(rectangular) or E (ellipsodial) projection technique. To...

Topics: DTIC Archive, Smith, R. B., RAYTHEON CO SUDBURY MA, *VULNERABILITY, *ERROR ANALYSIS, COMPUTATIONS,...

Liquid rocket booster integration study is presented. Volume 4 contains materials presented at the MSFC/JSC/KSC Integrated Reviews and Working Group Sessions, and the Progress Reviews presented to the KSC Study Manager. The following subject areas are covered: initial impact assessment; conflicts with the on-going STS mission; access to the LRB at the PAD; the activation schedule; transition requirements; cost methodology; cost modelling approach; and initial life cycle cost.

Topics: NASA Technical Reports Server (NTRS), BOOSTER ROCKET ENGINES, COSTS, MATHEMATICAL MODELS, RESEARCH...

A procedure is proposed for the assessment of the damage tolerance and collapse of stiffened composite panels using a single-stringer compression specimen. The dimensions of the specimen are determined such that the specimen s nonlinear response and collapse are representative of an equivalent multi-stringer panel in compression. Experimental tests are conducted on specimens with and without an embedded delamination. A shell-based finite element model with intralaminar and interlaminar damage...

Topics: NASA Technical Reports Server (NTRS), BUCKLING, COMPOSITE STRUCTURES, DAMAGE ASSESSMENT, CRACK...

Model-based prognostics approaches capture system knowledge in the form of physics-based models of components, and how they fail. These methods consist of a damage estimation phase, in which the health state of a component is estimated, and a prediction phase, in which the health state is projected forward in time to determine end of life. However, the damage estimation problem is often multi-dimensional and computationally intensive. We propose a model decomposition approach adapted from the...

Topics: NASA Technical Reports Server (NTRS), CENTRIFUGAL PUMPS, DECOMPOSITION, STRUCTURAL ENGINEERING,...

A sensitivity analysis is performed on a computer model of tree response to airblast loading. This effort was undertaken, with success, to reduce the number of input parameters required by the model to those available to the field commander. Based on the results of this analysis, a new prediction technique was developed which determines the extent of tree blowdown and the resultant effects on troop and vehicle movement. The technique was developed for inclusion in DNA Effects Manual Number 1.

Topics: DTIC Archive, Morris, Phillip J, URS RESEARCH CO SAN MATEO CA, *NUCLEAR EXPLOSION DAMAGE, *NUCLEAR...

Statistical procedures for shock models and wear processes are considered in this paper. We show that independent gamma-Dirichlet priors are conjugate priors when sampling from these shock models. Bayes rules given the observations are computed. In particular, we calculate the Bayes estimates of the survival probabilities for these models. We show consistency of the posterior distribution as well as weak convergence of the centered and suitably rescaled posterior processes. (Author)

Topics: DTIC Archive, Lo,Albert Y, CALIFORNIA UNIV BERKELEY OPERATIONS RESEARCH CENTER, *NONPARAMETRIC...

The purposes of the research are to develop a simplified fallout computational system for use in damage-assessment studies where very large numbers of weapons are used, and to develop a statistical procedure to relate wind variability to fallout pattern variability. The basic requirements of the simplified fallout computational system are that it simulate DELFIC fallout exposure rate contours and DELFIC accumulated exposure doses anywhere within the areas of significant fallout for identical...

Topics: DTIC Archive, Lee, Hong, STANFORD RESEARCH INST MENLO PARK CA, *COMPUTER PROGRAMS, *NUCLEAR...

This study is composed of three major parts, (1) effects of usage parameters on crack growth, (2) development of generalized procedures, and (3) implementation of the tracking program. During the development of generalized procedures, crack growth trends and alternate methods of tracking were established. In addition, the recorded data requirements have been evaluated. The effort regarding implementation of a tracking program consisted of an evaluation of logistics and the identification of...

Topics: DTIC Archive, Parker, G. S., MCDONNELL AIRCRAFT CO ST LOUIS MO, *CRACK PROPAGATION, *AIRFRAMES,...

The paper re-examines the physical assumptions which were made by the originators of the Miner-Palgren Rule for the calculation of fatigue life and cites publications which show that these assumptions, called the linear cumulative damage hypotheses, are contrary to our present knowledge about actual fatigue behavior. However, work is also discussed which provides evidence that Miner's Rule is better on the average in engineering applications than any other rule for fatigue life which has been...

Topics: DTIC Archive, Saunders, Sam C, BOEING SCIENTIFIC RESEARCH LABS SEATTLE WA MATHEMATICAL AND...

Suppose that shocks hit a device in accordance with a nonhomogeneous Poisson process with intensity function lambda(t). The ith shock causes a damage X sub i. The X sub i are assumed to be independent and identically distributed positive random variables, and are also assumed independent of the counting process of shocks. Let D(x sub 1, ..., x sub n) denote the total damage when n shocks having damages x sub 1, ..., x sub n have occurred. It has previously been shown that the first time that...

Topics: DTIC Archive, Ross,Sheldon M, CALIFORNIA UNIV BERKELEY OPERATIONS RESEARCH CENTER, *DAMAGE...

The present paper contains the model description for developing the damage parameters under the conditions of high rates of loading in impact experiments. The worked out methodology is illustrated on an example of processing the experimental results and spallation of organic materials to develop the critical dissipation energy. The results of the present investigations show that the dynamical wave pattern generated as a result of impact in the samples depends strongly on the damage parameters....

Topics: DTIC Archive, Smirnov, N. N., MOSCOW STATE UNIV (RUSSIA) FACULTY OF MECHANICS AND MATHEMATICS,...

Definition of crater related environments is influenced by a large number of variables potentially governing the phenomena. The large body of data is derived from many events of different character. A method to exploit this heterogeneous body for prediction is presented. Methods of dimensional analysis are used to reduce the number of independent variables through the introduction of nondimensional pi-groups. More importantly, this allows a common basis for comparing data from grossly...

Topics: DTIC Archive, Schmidt, R. M., BOEING CO SEATTLE WA, *CRATERING, DAMAGE ASSESSMENT, STATISTICAL...

This Technical Memorandum provides a macro-level description of the methodology implemented in UNICORN, an optimal weapon allocation computer model. The memorandum provides a discussion of the key UNICORN concepts and, where appropriate, the mathematical development of certain concepts used in the model. This document is intended for use in conjunction with the UNICORN (Version III) User's Manual, SAI-76-047-DEN. The discussion includes a brief model overview including capabilities and...

Topics: DTIC Archive, Blackwell,L M, SCIENCE APPLICATIONS INC ENGLEWOOD CO, *COMPUTERIZED SIMULATION,...

A pneumatic pistonphone simulator, developed by Wyle Laboratories, was used under the present contract to experimentally determine damage potential to single strength glass specimens when exposed to repetitive sonic booms. The glass specimen dimensions were typically 48 inch x 48 inch x 3/32 inch. In these experiments, particular emphasis was placed on the cumulative damage from a large number of booms. Preliminary static strength tests were conducted on two sizes of new (previously unused)...

Topics: DTIC Archive, Kao, George C, WYLE LABS HUNTSVILLE AL, *SONIC BOOM, BRITTLENESS, DAMAGE ASSESSMENT,...

Volume 2 contains supporting data for the details presented in Volume I. The report contains abstracts for the 32 technical reports reviewed during the program. Included in the literature survey section is a matrix categorization of the reports by subject and applicable areas of interest. A brief description is presented on STAGS, the LMSC computer program used to perform the analysis of the P2V-4 fuselage bumper. A comprehensive description of program KRASH is presented, including the theory,...

Topics: DTIC Archive, Wittlin, Gilbert, LOCKHEED-CALIFORNIA CO BURBANK, *HELICOPTERS, *AVIATION ACCIDENTS,...

The results of a four-phase study to develop helicopter structural crashworthiness analytical and design techniques are presented. The study consisted of the development of a computer program (KRASH) and the verification of a mathematical model to predict the dynamic response during a survivable accident in which combined vertical and lateral impact velocities are present. Included in the study were a literature survey and evaluation, a detailed analysis of 32 accident cases, a drop test of a...

Topics: DTIC Archive, Wittlin, Gilbert, LOCKHEED-CALIFORNIA CO BURBANK, *HELICOPTERS, *AVIATION ACCIDENTS,...

In thin composite laminates, the first level of visible damage occurs in the back face and is called back face spalling. A plate-membrane coupling model, and a finite element model to analyze the large deformation behavior of eight-ply quasi-isotropic circular composite plates under impact type point loads are developed. The back face spalling phenomenon in thin composite plates is explained by using the plate-membrane coupling model and the finite element model in conjunction with the fracture...

Topics: NASA Technical Reports Server (NTRS), DAMAGE ASSESSMENT, FINITE ELEMENT METHOD, FRACTURE MECHANICS,...

The excellent mechanical properties of carbon-nanotubes are driving research into the creation of new strong, tough nanocomposite systems. In this program, our initial work presented the first evidence of toughening mechanisms operating in carbon-nanotube- reinforced ceramic composites using a highly-ordered array of parallel multiwall carbon-nanotubes (CNTs) in an alumina matrix. Nanoindentation introduced controlled cracks and the damage was examined by SEM. These nanocomposites exhibit the...

Topics: NASA Technical Reports Server (NTRS), CERAMIC MATRIX COMPOSITES, CARBON NANOTUBES, DAMAGE...

The concept of life extending control is defined. A brief discussion of current fatigue life prediction methods is given and the need for an alternative life prediction model based on a continuous functional relationship is established. Two approaches to life extending control are considered: (1) the implicit approach which uses cyclic fatigue life prediction as a basis for control design; and (2) the continuous life prediction approach which requires a continuous damage law. Progress on an...

Topics: NASA Technical Reports Server (NTRS), FATIGUE LIFE, MATHEMATICAL MODELS, NONLINEAR PROGRAMMING,...

Environmental fatigue crack propagation rates and microscopic damage modes in Al-Li-Cu alloy 2090 (Parts 1 and 2) are described by a crack tip process zone model based on hydrogen embrittlement. Da/dN sub ENV equates to discontinuous crack advance over a distance, delta a, determined by dislocation transport of dissolved hydrogen at plastic strains above a critical value; and to the number of load cycles, delta N, required to hydrogenate process zone trap sites that fracture according to a...

Topics: NASA Technical Reports Server (NTRS), ALUMINUM ALLOYS, COPPER ALLOYS, CRACK PROPAGATION, CRACK...

The Vulnerability Model (VM) is a computer simulation intended to provide quantitative measures of the consequences of maritime spills of hazardous materials. The simulation starts with a description of the nature of the spill itself, continues through the dispersion of the hazardous material, and then assesses the effects of resulting toxicity, fire and/or explosion, as applicable, on people and property. This report describes the third-stage development of the VM, which consisted of improving...

Topics: DTIC Archive, Rausch, Andre H., ENVIRO CONTROL INC ROCKVILLE MD, *DAMAGE ASSESSMENT, *HAZARDOUS...

Four microbarograph stations recorded waves at a range of approximately 130 mi from a row charge of high explosives buried near optimum cratering depth. Comparison with propagations from three airburst calibration detonations showed that a source model derived from close-in data was appropriate for distant effects predictions. This model predicted that wave amplitudes from explosives at this scaled depth would be 20% of amplitudes expected for a free air burst. All amplitudes perpendicular to a...

Topics: DTIC Archive, Reed, Jack W, SANDIA NATIONAL LABS ALBUQUERQUE NM, *NUCLEAR EXPLOSIONS, *CRATERING,...

This paper describes a series of modal tests that were performed on a cantilevered truss structure. The goal of the tests was to assemble a large database of high quality modal test data for use in verification of proposed methods for on orbit model verification and damage detection in flexible truss structures. A description of the hardware is provided along with details of the experimental setup and procedures for 16 damage cases. Results from selected cases are presented and discussed....

Topics: NASA Technical Reports Server (NTRS), DAMAGE ASSESSMENT, FLEXIBLE SPACECRAFT, GROUND TESTS, LARGE...

This report addresses the development of a model for blast propagation in compartmented structures with progressively failing thin structural elements like windows. The mathematical model is based on the assumption that the frangible structural features (a) are thin compared to the characteristic length scale, (b) do not deform much before breakage, and (c) fail instantaneously when the corresponding accumulated damage reaches some threshold. The presented numerical model employs a variation of...

Topics: DTIC Archive, DEFENCE SCIENCE AND TECHNOLOGY ORGANISATION EDINBURGH (AUSTRALIA) WEAPONS SYSTEMS...

The multiple mesh/single stage dynamics program is a gear tooth analysis program which determines detailed geometry, dynamic loads, stresses, and surface damage factors. The program can analyze a variety of both epicyclic and single mesh systems with spur or helical gear teeth including internal, external, and buttress tooth forms. The modifications refine the options for the flexible carrier and flexible ring gear rim and adds three options: a floating Sun gear option; a natural frequency...

Topics: NASA Technical Reports Server (NTRS), DAMAGE ASSESSMENT, DYNAMIC LOADS, GEAR TEETH, MATHEMATICAL...

The study was directed toward identifying the essential subsystems and components of metropolitan gas and electric utility systems, determining their functional relationships, estimating the damage to critical elements from various nuclear weapons effects, and estimating the repair requirements for restoring damaged systems. A mathematical repair model was developed and applied to 'typical' city, and from the results of the study, time repair effort including manpower by skills, was derived....

Topics: DTIC Archive, Van Horn, William H, URS SYSTEMS CORP BURLINGAME CA, *NUCLEAR EXPLOSION DAMAGE,...

The results of an experimental/numerical campaign aimed to develop progressive damage analysis (PDA) tools for predicting the strength of a composite bonded joint under tensile loads are presented. The PDA is based on continuum damage mechanics (CDM) to account for intralaminar damage, and cohesive laws to account for interlaminar and adhesive damage. The adhesive response is characterized using standard fracture specimens and digital image correlation (DIC). The displacement fields measured by...

Topics: NASA Technical Reports Server (NTRS), BONDED JOINTS, ADHESIVES, COHESION, CONTINUUM MECHANICS,...

A very integral part of the Army HAVE NAME vulnerability model was the internal distribution factor for the Army selected target, a HAWK battery. This internal distribution factor had to be measured using a major item of a Hawk battery. Because of the possible damage carbon fibers might cause to the electrical/electronic components of a Hawk major item, it was necessary to measure the internal distribution factor using a non-conducting, aerodynamic simulant for carbon fibers. This report...

Topics: DTIC Archive, Braerman, William F., ARMY BALLISTIC RESEARCH LAB ABERDEEN PROVING GROUND MD,...